Endocrine Abstracts

JOINT3304

Introduction: Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterized by excessive parathyroid hormone secretion. While it is often associated with medullary thyroid carcinoma (MTC) in the context of multiple endocrine neoplasia type 2 (MEN2), its association with papillary thyroid carcinoma (PTC) remains rare (1,2). Here, we report an exceptional case of this coexistence.

Case Report: A 67-year-old woman with type 2 diabetes complicated by chronic kidney disease was referred to endocrinology for hypercalcemia. Biological investigations confirmed PHPT. Cervical ultrasound showed multiple thyroid nodules, with the most concerning located in the right mediolobar region, measuring 5.4 × 4.6 × 4 mm and classified as EU-TIRADS V. It also revealed a hypoechoic lesion beneath the thyroid, suggestive of a parathyroid adenoma with a maximum diameter of 13 mm. This finding was confirmed by parathyroid scintigraphy, which identified a subisthmic parathyroid adenoma. Calcitonin levels were negative. A total thyroidectomy and parathyroidectomy were performed. Histopathological examination revealed an invasive micropapillary thyroid carcinoma (0.5 cm) in the right lobe, associated with a parathyroid adenoma. Postoperative assessment showed normalization of serum calcium and PTH levels, with complete remission achieved after a course of radioiodine (I-131) therapy.

Discussion & Conclusion: The co-occurrence of PTC and PHPT has been reported in 2.3–4.3% of patients undergoing surgery for PHPT (3). The underlying pathological mechanism linking these two conditions remains poorly understood and has not yet been fully elucidated. Current hypotheses point to the involvement of embryological factors and shared genetic pathways (1). Although this association is considered rare, recognizing it in clinical practice is essential to ensure an optimal management strategy for both conditions and improve patient outcomes (4).

References: 1. Ben Nasr, M., Ben Sellem, D., Belayouni, R., Zaabar, L., Letaief, B., & Mhiri, A. (2024). À propos d’une association rare: hyperparathyroïdie primaire et carcinome papillaire de la thyroïde. Médecine Nucléaire, 48(2), 74. https://doi.org/10.1016/j.mednuc.2024.01.057.2. Jha, S., & Simonds, W. F. (2023). Molecular and clinical spectrum of primary hyperparathyroidism. Endocrine Reviews, 44(6), 779–818. https://doi.org/10.1210/endrev/bnad0093. Bakari, H. et al. (2024). Découverte fortuite d’un carcinome papillaire multifocal (CPT) de la thyroïde dans les suites d’une hyperparathyroïdie primaire: à propos d’un cas. Médecine Nucléaire, 48(2), 91. https://doi.org/10.1016/j.mednuc.2024.01.1034. Abidi, I., Rifai, K., Iraqi, H., & Gharbi, M. E. H. (2021). À propos d’une association rare: hyperparathyroïdie primaire multifocale et carcinome papillaire de la thyroïde. Annales d’Endocrinologie, 82(5), 395–396. https://doi.org/10.1016/j.ando.2021.08.404